侵蚀环境下矮塔斜拉桥时变承载力研究与评定  

Research and evaluation of time-varying bearing capacity of cable-stayed bridge with low tower in corrosive environment

作　　者：周雨洁 宋旭明[1] 唐冕[1] 李金鹏 ZHOU Yujie;SONG Xuming;TANG Mian;LI Jinpeng(School of Civil Engineering,Central South University,Changsha 410075,China;China Railway Design Group Co.,Ltd.,Engineering Economic Design and Research Institute,Tianjin 300308,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中国铁路设计集团有限公司工程经济设计研究院,天津300308

出　　处：《铁道科学与工程学报》2022年第10期3005-3015,共11页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52078486)。

摘　　要：矮塔斜拉桥造型独特、美观大方、经济合理,近年来在国内外应用广泛。为了研究其在侵蚀环境下的承载能力随时间的变化规律、评定桥梁的工作状态,以我国东部沿海地区某在役刚构体系矮塔斜拉桥为工程背景,通过全桥有限元模型得出矮塔斜拉桥的最不利受力位置,探讨墩、塔等关键构件合适的混合单元模拟方式,分析得到精度和效率均较高的单元比例系数。采用ANSYS建立梁单元与实体单元相结合的精细化混合有限元模型,分析斜拉索、钢筋和混凝土等多种劣化因素影响下的桥梁时变承载力的变化规律。研究结果表明:在第20~30年间,斜拉索锈蚀对刚构体系矮塔斜拉桥承载力的影响尤其显著,经过每20年换索后,拉索可始终处于良好的力学性能状态;第30~60年间,影响桥梁承载力的主要因素为混凝土的劣化等因素,在60年之后预应力钢筋锈蚀加剧,结构的承载力降低速率加快。参照《公路桥梁承载能力检测评定规程》,在计算混凝土和钢筋的截面折减系数的基础上拟合出桥梁承载力的时变表达式,引入承载力恶化变量,发现其与时间呈现负相关,为同类桥梁在侵蚀环境下的时变承载力评估提供参考。Cable-stayed bridges with low towers are unique in shape,elegant in appearance,economical and reasonable,which have been widely used in China and abroad in recent years.In order to study the changing law of its bearing capacity with time in erosive environment and to evaluate the working state of the bridge,an in-service rigid-frame system low-tower cable-stayed bridge in the eastern coastal area in China was taken as the engineering background.The finite element model of the whole bridge was used to obtain the most unfavorable force-bearing position of the cable-stayed bridge with a short tower.The appropriate hybrid element simulation method for key components such as piers and towers was discussed,and the element proportionality coefficient with high accuracy and efficiency was obtained through analysis.The ANSYS software program was used to establish a refined hybrid finite element model combining beam elements and solid elements,and the change law of the bridge’s time-varying bearing capacity under the influence of various deterioration factors such as stay cables,steel bars and concrete was analyzed.The research results show that in the 20th to 30th years,the corrosion of the stay cables has a particularly significant effect on the bearing capacity of the rigid-frame cable-stayed bridge with low-tower.After the cables were replaced every 20 years,the stay cables can always be in a state of good mechanical properties;From the 30th to the 60th year,the main factors affecting the bearing capacity of the bridge are the deterioration of concrete and other factors.Referring to the“Regulations for Testing and Evaluation of Bearing Capacity of Highway Bridges”,the time-varying expression of the bearing capacity of the bridge is fitted based on calculating the reduction coefficient of the section of concrete and steel bars,and the deterioration variable of bearing capacity is introduced.It is found that it is negatively correlated with time.It provides a reference for the time-varying bearing capacity evaluati

关 键 词：矮塔斜拉桥 混合单元 时变承载力 侵蚀劣化 承载力评定 

分 类 号：U24[交通运输工程—道路与铁道工程]